This invention is in the field of electronic vidicon camera tubes, and, in particular, those tubes usable at infrared wavelengths. The only generally known types of infrared vidicons at present are those with pyroelectric retinas (also called targets or signal plates). Regardless of the type of retina used, the greatest problem in the manufacture of camera tubes (and other types of vacuum tubes as well) is that of removing or reducing contamination, particularly those contaminants which might remain in the tube after all its elements are in place and final vacuum pumping is finished. The contaminants can be in the form of submicroscopic particles, gases, or vapors, and are partially removed by baking the tubes under vacuum, after all elements, i.e., grids, electron gun, retina, etc. are in place. One of the final steps in tube manufacture is the firing of a "getter" inside the tube. This getter includes an alkali metal which is evaporated and whose ions combine with ions of contamination in the tube; the evaporated metal (and the ions with which it combined) condenses on the tube walls or is pumped out of the tube. All of the baking, pumping, and firing of a getter are well known in tube manufacture, but cannot be directly used with a pyroelectric retina. This is because the normal baking temperatures may exceed 450.degree. C. and the fact that the TGS (triglycine sulfate) family of retina materials have relatively low melting points (233.degree. C. for TGS) and visibly char in short times at the melting points (less than a minute for TGS). The present invention teaches a method of making a pyroelectric vidicon that avoids the problem of retina charing.